Sja-miR-71a in Schistosome egg-derived extracellular vesicles suppresses liver fibrosis caused by schistosomiasis via targeting semaphorin 4D

Sja-let-7 suppresses the development of liver fibrosis via Schistosoma japonicum extracellular vesicles

Schistosomiasis is a fatal zoonotic parasitic disease that also threatens human health. The main pathological features of schistosomiasis are granulomatous inflammation and subsequent liver fibrosis, which is a complex, chronic, and progressive disease. Extracellular vesicles (EVs) derived from schistosome eggs are broadly involved in host-parasite communication and act as important contributors to schistosome-induced liver fibrosis. However, it remains unclear whether substances secreted by the EVs of Schistosoma japonicum, a long-term parasitic "partner" in the hepatic portal vein of the host, also participate in liver fibrosis. Here, we report that EVs derived from S. japonicum worms attenuated liver fibrosis by delivering sja-let-7 into hepatic stellate cells (HSCs). Mechanistically, activation of HSCs was reduced by targeting collagen type I alpha 2 chain (Col1α2) and downregulation of the TGF-β/Smad signaling pathway both in vivo and in vitro. Overall, these results contribute to further understanding of the molecular mechanisms underlying host-parasite interactions and identified the sja-let-7/Col1α2/TGF-β/Smad axis as a potential target for treatment of schistosomiasis-related liver fibrosis.

Potential i-Nos/Arg-1 Switch with NLRP3 and Parasitic Load Down Regulation in Experimental Schistosoma mansoni Infection via Chloroquine Repurposing

In previous studies, the inhibitory effect of chloroquine on NLRP3 inflammasome and heme production was documented. This may be employed as a double-bladed sword in schistosomiasis (anti-inflammatory and parasiticidal). In this study, chloroquine's impact on schistosomiasis mansoni was investigated. The parasitic load (worm/egg counts and reproductive capacity index [RCI]), i-Nos/Arg-1 expression, splenomegaly, hepatic insult and NLRP3-immunohistochemical expression were assessed in infected mice after receiving early and late repeated doses of chloroquine alone or dually with praziquantel. By early treatment, the least RCI was reported in dually treated mice (41.48 ± 28.58) with a significant reduction in worm/egg counts (3.50 ± 1.29/2550 ± 479.58), compared with either drug alone. A marked reduction in the splenic index was achieved by prolonged chloroquine administration (alone: 43.15 ± 5.67, dually: 36.03 ± 5.27), with significantly less fibrosis (15 ± 3.37, 14.25 ± 2.22) than after praziquantel alone (20.5 ± 2.65). Regarding inflammation, despite the praziquantel-induced significant decrease in NLRP3 expression, the inhibitory effect was marked after dual and chloroquine administration (liver: 3.13 ± 1.21/3.45 ± 1.23, spleen: 5.7 ± 1.6/4.63 ± 2.41). i-Nos RNA peaked with early/late chloroquine administration (liver: 68.53 ± 1.8/57.78 ± 7.14, spleen: 63.22 ± 2.06/62.5 ± 3.05). High i-Nos echoed with a parasiticidal and hepatoprotective effect and may indicate macrophage-1 polarisation. On the flip side, the chloroquine-induced low Arg-1 seemed to abate immune tolerance and probably macrophage-2 polarisation. Collectively, chloroquine synergised the praziquantel-schistosomicidal effect and minimised tissue inflammation, splenomegaly and hepatic fibrosis.

The knowns and unknowns of helminth-host miRNA cross-kingdom communication

MicroRNAs (miRNAs) are small noncoding RNAs that oversee gene modulation. They are integral to cellular functions and can migrate between species, leading to cross-kingdom gene suppression. Recent breakthroughs in helminth genome studies have sparked curiosity about helminth RNA regulators and their ability to regulate genes across species. Growing data indicate that helminth miRNAs have a significant impact on the host's immune system. Specific miRNAs from helminth parasites can merge with the host's miRNA system, implying that parasites could exploit their host's regulatory machinery and function. This review highlights the role of cross-kingdom helminth-derived miRNAs in the interplay between host and parasite, exploring potential routes for their uptake, processing, and consequences in host interaction.

Schistosome egg-derived extracellular vesicles deliver Sja-miR-71a inhibits host macrophage and neutrophil extracellular traps via targeting Sema4D

BACKGROUND

Macrophages and neutrophils are rapidly recruited around Schistosome eggs to form granulomas. Extracellular traps (ETs) of macrophages and neutrophils are part of the pathogen clearance armamentarium of leukocytes. Schistosome eggs possess the ability to resist attack by the host's immune cells and survive by employing various immune evasion mechanisms, including the release of extracellular vesicles (EVs). However, the specific mechanisms by which Schistosome egg-derived EVs (E-EVs) evade the immune response and resist attack from macrophage and neutrophil ETs remain poorly understood. In this study, we aimed to investigate the association between E-EVs and macrophage/neutrophil ETs.

METHODS

EVs were isolated from the culture supernatant of S. japonicum eggs and treated macrophages and neutrophils with E-EVs and Sja-miR-71a. The formation of ETs was then observed. Additionally, we infected mice with S. japonicum, administered HBAAV2/9-Sja-miR-71a, and the formation of macrophage ETs (METs) and neutrophil ETs (NETs) in the livers was measured. Sema4D-knockout mice, RNA sequencing, and trans-well assay were used to clarify Sja-miR-71a in E-EVs inhibits METs and NETs formation via the Sema4D/ PPAR-γ/ IL-10 axis.

RESULTS

Our findings revealed that E-EVs were internalized by macrophages and neutrophils, leading to the inhibition of METs and NETs formation. The highly expressed Sja-miR-71a in E-EVs targeted Sema4D, resulting in the up-regulation of IL-10 and subsequent inhibition of METs and NETs formation. Sema4D knockout up-regulated IL-10 expression and inhibited the formation of METs and NETs. Furthermore, we further demonstrated that Sja-miR-71a inhibits METs and NETs formation via the Sema4D/ PPAR-γ/ IL-10 axis.

CONCLUSIONS

In summary, our findings provide new insights into the immune evasion abilities of Schistosome eggs by demonstrating their ability to inhibit the formation of METs and NETs through the secretion of EVs. This study enhances our understanding of the host-pathogen interaction and may have implications for the development of novel therapeutic approaches. Video Abstract.

MicroRNAs in infectious diseases: potential diagnostic biomarkers and therapeutic targets

MicroRNAs (miRNAs) are conserved, short, non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They have been implicated in the pathogenesis of cancer and neurological, cardiovascular, and autoimmune diseases. Several recent studies have suggested that miRNAs are key players in regulating the differentiation, maturation, and activation of immune cells, thereby influencing the host immune response to infection. The resultant upregulation or downregulation of miRNAs from infection influences the protein expression of genes responsible for the immune response and can determine the risk of disease progression. Recently, miRNAs have been explored as diagnostic biomarkers and therapeutic targets in various infectious diseases. This review summarizes our current understanding of the role of miRNAs during viral, fungal, bacterial, and parasitic infections from a clinical perspective, including critical functional mechanisms and implications for their potential use as biomarkers and therapeutic targets.

Sja-Let-7 Attenuates Carbon Tetrachloride-Induced Liver Fibrosis in a Mouse Model via Col1α2

Liver fibrosis (LF) is a chronic progressive disease with no definitive treatment. The aim of this study was to assess helminth-derived molecules as potential therapeutic targets to prevent or reverse LF. A mouse model of carbon tetrachloride (CCL4)-induced LF was established and sja-let-7 was overexpressed by treatment with a miRNA agomir once per week. After four weeks, serum biochemistry, hepatic hydroxyproline content measurements, liver histology, mRNA expression profiling of fibrotic markers, the dual-luciferase reporter assay, and fluorescence in situ hybridization (FISH) were performed. Administration of the sja-let-7 agomir markedly ameliorated hepatosplenomegaly and reduced the liver hydroxyproline content. Liver histological analysis showed significant reductions in collagen deposition in the sja-let-7 agomir-treated mice. Additionally, the mRNA levels of both pro-fibrotic markers and pro-inflammatory cytokines were diminished after treatment. Furthermore, the dual-luciferase reporter assay and FISH identified the α2 chain of collagen type 1 (Col1α2) as the direct target of sja-let-7. Accordingly, the progression of LF was attenuated by targeting Col1α2 and the TGF-β/Smad signaling pathway.

microRNA silencing in a whole worm cestode model provides insight into miR-71 function

Parasites belonging to the class Cestoda include zoonotic species such as Echinococcus spp. and Taenia spp. that cause morbidity and mortality in endemic areas, mainly affecting pastoral and rural communities in low income countries but also upper middle income countries. Cestodes show remarkable developmental plasticity, implying tight regulation of gene expression throughout their complex life cycles. Despite the recent availability of genomic data for cestodes, little progress was made on postgenomic functional studies. MicroRNAs (miRNAs) are key components of gene regulatory systems that guide diverse developmental processes in multicellular organisms. miR-71 is a highly expressed miRNA in cestodes, which is absent in vertebrates and targets essential parasite genes, representing a potential key player in understanding the role of miRNAs in cestodes biology. Here we used transfection with antisense oligonucleotides to perform whole worm miRNA knockdown in tetrathyridia of Mesocestoides vogae (syn. Mesocestoides corti), a laboratory model of cestodes. We believe this is the first report of miRNA knockdown at the organism level in these parasites. Our results showed that M. vogae miR-71 is involved in the control of strobilation in vitro and in the establishment of murine infection. In addition, we identified miR-71 targets in M. vogae, several of them being de-repressed upon miR-71 knockdown. This study provides new knowledge on gene expression regulation in cestodes and suggests that miRNAs could be evaluated as new selective therapeutic targets for treating Neglected Tropical Diseases prioritised by the World Health Organization.

microRNAs in parasite-induced liver fibrosis: from mechanisms to diagnostics and therapeutics

Chronic parasite infections in the liver pose a global threat to human and animal health, often occurring with liver fibrosis that leads to cirrhosis, liver failure, and even cancer. Hepatic fibrogenesis is a complex yet reversible process of tissue repair and is associated with various factors, including immune cells, microenvironment, gut microbiome, and interactions of the different liver cells. As a profibrogenic or antifibrogenic driver, microRNAs (miRNAs) are closely involved in parasite-induced hepatic fibrosis. This article updates the current understanding of the roles of miRNAs in hepatic fibrogenesis by parasite infections and discusses the strategies using miRNAs as candidates for diagnostics and therapeutics.

Sleep Deprivation Promotes Endothelial Inflammation and Atherogenesis by Reducing Exosomal miR-182-5p

BACKGROUND

Insufficient or disrupted sleep increases the risk of cardiovascular disease, including atherosclerosis. However, we know little about the molecular mechanisms by which sleep modulates atherogenesis. This study aimed to explore the potential role of circulating exosomes in endothelial inflammation and atherogenesis under sleep deprivation status and the molecular mechanisms involved.

METHODS

Circulating exosomes were isolated from the plasma of volunteers with or without sleep deprivation and mice subjected to 12-week sleep deprivation or control littermates. miRNA array was performed to determine changes in miRNA expression in circulating exosomes.

RESULTS

Although the total circulating exosome levels did not change significantly, the isolated plasma exosomes from sleep-deprived mice or human were a potent inducer of endothelial inflammation and atherogenesis. Through profiling and functional analysis of the global microRNA in the exosomes, we found miR-182-5p is a key exosomal cargo that mediates the proinflammatory effects of exosomes by upregulation of MYD88 (myeloid differentiation factor 88) and activation of NF-ĸB (nuclear factor kappa-B)/NLRP3 pathway in endothelial cells. Moreover, sleep deprivation or the reduction of melatonin directly decreased the synthesis of miR-182-5p and led to the accumulation of reactive oxygen species in small intestinal epithelium.

CONCLUSIONS

The findings illustrate an important role for circulating exosomes in distant communications, suggesting a new mechanism underlying the link between sleep disorder and cardiovascular disease.

Small extracellular vesicles but not microvesicles from Opisthorchis viverrini promote cell proliferation in human cholangiocytes

Chronic infection with O. viverrini has been linked to the development of cholangiocarcinoma (CCA), which is a major public health burden in the Lower Mekong River Basin countries, including Thailand, Lao PDR, Vietnam and Cambodia. Despite its importance, the exact mechanisms by which O. viverrini promotes CCA are largely unknown. In this study, we characterized different extracellular vesicle populations released by O. viverrini (OvEVs) using proteomic and transcriptomic analyses and investigated their potential role in host-parasite interactions. While 120k OvEVs promoted cell proliferation in H69 cells at different concentrations, 15k OvEVs did not produce any effect compared to controls. The proteomic analysis of both populations showed differences in their composition that could contribute to this differential effect. Furthermore, the miRNAs present in 120k EVs were analysed and their potential interactions with human host genes was explored by computational target prediction. Different pathways involved in inflammation, immune response and apoptosis were identified as potentially targeted by the miRNAs present in this population of EVs. This is the first study showing specific roles for different EV populations in the pathogenesis of a parasitic helminth, and more importantly, an important advance towards deciphering the mechanisms used in establishment of opisthorchiasis and liver fluke infection-associated malignancy.

Hepatocyte-derived MASP1-enriched small extracellular vesicles activate HSCs to promote liver fibrosis

BACKGROUND AND AIMS

Liver fibrosis is a chronic disease characterized by different etiological agents; dysregulated interactions between hepatocytes and HSCs contribute to this disease. β-arrestin 1 (ARRB1) plays an important role in liver fibrosis; however, the effect of ARRB1 on the crosstalk between hepatocytes and HSCs in liver fibrosis is unknown. The aim of this study is to investigate how ARRB1 modulates hepatocyte and HSC activation during liver fibrosis.

APPROACH AND RESULTS

Normal and fibrotic human liver and serum samples were obtained. CCl 4 -induced liver fibrosis and methionine-choline deficiency-induced NASH models were constructed. Primary hepatocytes and HSCs were isolated, and human hepatic LO2 and stellate LX2 cells were used. Small extracellular vesicles (EVs) were purified, and key proteins were identified. ARRB1 was up-regulated in hepatocytes and associated with autophagic blockage in liver fibrosis. ARRB1 increased the release of hepatocyte-derived small EVs by inhibiting multivesicular body lysosomal degradation and activating Rab27A, thereby activating HSCs. Proteomic analyses showed that mannan-binding lectin serine protease 1 (MASP1) was enriched in hepatocyte-derived small EVs and activated HSCs via p38 mitogen-activated protein kinase (MAPK)/activating transcription factor 2 (ATF2) signaling. ARRB1 up-regulated MASP1 expression in hepatocytes. MASP1 promoted liver fibrosis in mice. Clinically, MASP1 expression was increased in the serum and liver tissue of patients with liver fibrosis.

CONCLUSIONS

ARRB1 up-regulates the release of hepatocyte-derived MASP1-enriched small EVs by regulating the autophagic-lysosomal/multivesicular body pathway and Rab27A. Hepatocyte-derived MASP1 activates HSCs to promote liver fibrogenesis through p38 MAPK/ATF2 signaling. Thus, MASP1 is a pivotal therapeutic target in liver fibrosis.

Differential Analysis of Key Proteins Related to Fibrosis and Inflammation in Soluble Egg Antigen of Schistosoma mansoni at Different Infection Times

Schistosomiasis is a major global health problem. Schistosomes secrete antigens into the host tissue that bind to chemokines or inhibit immune cell receptors, regulating the immune responses to allow schistosome development. However, the detailed mechanism of chronic schistosome infection-induced liver fibrosis, including the relationship between secreted soluble egg antigen (SEA) and hepatic stellate cell (HSC) activation, is still unknown. We used mass spectrometry to identify the SEA protein sequences from different infection weeks. In the 10th and 12th infection weeks, we focused on the SEA components and screened out the special protein components, particularly fibrosis- and inflammation-related protein sequences. Our results have identified heat shock proteins, phosphorylation-associated enzymes, or kinases, such as Sm16, GSTA3, GPCRs, EF1-α, MMP7, and other proteins linked to schistosome-induced liver fibrosis. After sorting, we found many special proteins related to fibrosis and inflammation, but studies proving their association with schistosomiasis infection are limited. Follow-up studies on MICOS, MATE1, 14-3-3 epsilon, and CDCP1 are needed. We treated the LX-2 cells with the SEA from the 8th, 10th, and 12th infection weeks to test HSC activation. In a trans-well cell model in which PBMCs and HSCs were co-cultured, the SEA could significantly induce TGF-β secretion, especially from the 12th week of infection. Our data also showed that TGF-β secreted by PBMC after the SEA treatment activates LX-2 and upregulates hepatic fibrotic markers α-SMA and collagen 1. Based on these results, the CUB domain-containing protein 1 (CDCP1) screened at the 12th infection week could be investigated further. This study clarifies the trend of immune mechanism variation in the different stages of schistosome infection. However, how egg-induced immune response transformation causes liver tissue fibrosis needs to be studied further.

Single-sex schistosomiasis: a mini review

Schistosomiasis is a neglected tropical disease caused by dioecious blood flukes of the genus Schistosoma and second to malaria as a parasitic disease with significant socio-economic impacts. Mating is essential for maturation of male and female schistosomes and for females to lay of eggs, which are responsible for the pathogenesis and propagation of the life cycle beyond the mammalian host. Single-sex schistosomes, which do not produce viable eggs without mating, have been overlooked given the symptomatic paucity of the single-sex schistosomiasis and limited diagnostic toolkit. Besides, single-sex schistosomes are less sensitive to praziquantel. Therefore, these issues should be considered to achieve the elimination of this infection disease. The aim of this review is to summarize current progress in research of single-sex schistosomes and host-parasite interactions.

Pathology and molecular mechanisms of Schistosoma japonicum-associated liver fibrosis

Schistosomiasis has been widely disseminated around the world, and poses a significant threat to human health. Schistosoma eggs and soluble egg antigen (SEA) mediated inflammatory responses promote the formation of egg granulomas and liver fibrosis. With continuous liver injuries and inflammatory stimulation, liver fibrosis can develop into liver cirrhosis and liver cancer. Therefore, anti-fibrotic therapy is crucial to increase the survival rate of patients. However, current research on antifibrotic treatments for schistosomiasis requires further exploration. In the complicated microenvironment of schistosome infections, it is important to understand the mechanism and pathology of schistosomiasis-associated liver fibrosis(SSLF). In this review, we discuss the role of SEA in inhibiting liver fibrosis, describe its mechanism, and comprehensively explore the role of host-derived and schistosome-derived microRNAs (miRNAs) in SSLF. Inflammasomes and cytokines are significant factors in promoting SSLF, and we discuss the mechanisms of some critical inflammatory signals and pro-fibrotic cytokines. Natural killer(NK) cells and Natural killer T(NKT) cells can inhibit SSLF but are rarely described, therefore, we highlight their significance. This summarizes and provides insights into the mechanisms of key molecules involved in SSLF development.

Demethylzeylasteral attenuates hepatic stellate cell activation and liver fibrosis by inhibiting AGAP2 mediated signaling

BACKGROUND

Liver fibrosis is a common cause of chronic liver disease. If left untreated, it can ultimately develop into liver cirrhosis or hepatocellular carcinoma. However, a direct antifibrotic therapy is currently unavailable. A re-examination of existing chemicals might be a potential strategy for finding more lead compounds against liver fibrosis. Demethylzeylasteral (T-96), a naturally occurring bioactive compound found in Tripterygium wilfordii Hook. f. (TwHf) possesses multiple pharmacological properties. However, its antifibrotic potential has not yet been fully evaluated.

PURPOSE

This study aimed to investigate the antifibrotic properties of T-96 and its underlying molecular mechanisms.

METHODS

The antifibrotic properties of T-96 were investigated in three types of hepatic stellate cells (HSCs) and in a CCl₄-induced liver fibrosis mouse model. The effect of T-96 on the proliferation, migration, and activation of HSCs was detected using CCK-8 and scratch/wound healing assays. Hepatic inflammation and fibrosis were evaluated by H&E, Masson's trichrome stain, and Sirius Red staining. The expression of inflammatory and fibrogenic genes was detected by quantitative real-time PCR (qRT-PCR) and western blotting. RNA sequencing (RNA-seq) was performed to explore the potential molecular mechanisms mediating the antifibrotic effect of T-96, which was verified by dual-luciferase reporter assay, qRT-PCR, western blotting, immunofluorescence, and immunoprecipitation analysis.

RESULTS

The T-96 treatment significantly suppressed the proliferation, migration, and activation of HSCs in vitro. The administration of T-96 attenuated hepatic injury, inflammation, and fibrosis progression in mice with CCl₄-induced liver fibrosis. In addition, the RNA-seq of fibrotic liver tissues and subsequent functional verification indicated that the key mechanisms of the antifibrotic effect of T-96 were mediated by suppressing the expression of AGAP2 (Arf GAP with GTPase-like domain, ankyrin repeat and PH domain 2), inhibiting the subsequent phosphorylation of focal adhesion kinase (FAK) and protein kinase B (AKT), and finally reducing the expression of fibrosis-related genes.

CONCLUSION

Our results provide the first insight that T-96 exerts potent antifibrotic effects both in vitro and in vivo by inhibiting the AGAP2 mediated FAK/AKT signaling axis, and that T-96 may serve as a potential therapeutic candidate for the treatment of liver fibrosis.

Diagnostic Potential of microRNAs in Extracellular Vesicles Derived from Bronchoalveolar Lavage Fluid for Pneumonia—A Preliminary Report

Current clinical needs require the development and use of rapid and effective diagnostic indicators to accelerate the identification of pneumonia and the process of microbiological diagnosis. MicroRNAs (miRNAs) in extracellular vesicles (EVs) have become attractive candidates for novel biomarkers to evaluate the presence and progress of many diseases. We assessed their performance as biomarkers of pneumonia. Patients were divided into the pneumonia group (with pneumonia) and the control group (without pneumonia). We identified and compared two upregulated miRNAs in EVs derived from bronchoalveolar lavage fluid (BALF-EVs) between the two groups (P_{miR–17–5p} = 0.009; P_{miR–193a–5p} = 0.031). Interestingly, in cell-debris pellets and EVs-free supernatants derived from bronchoalveolar lavage fluid (BALF-cell-debris pellets and BALF-EVs-free supernatants), total plasma, and EVs derived from plasma (plasma-EVs), the expression of miR–17–5p and miR–193a–5p showed no difference between pneumonia group and control group. In vitro experiments revealed that miR–17–5p and miR–193a–5p were strikingly upregulated in EVs derived from macrophages stimulated by lipopolysaccharide. MiR–17–5p (area under the curve, AUC: 0.753) and miR–193a–5p (AUC: 0.692) in BALF-EVs are not inferior to procalcitonin (AUC: 0.685) in the diagnosis of pneumonia. Furthermore, miR–17–5p and miR–193a–5p in BALF-EVs had a significantly higher specificity compared to procalcitonin and could be served as a potential diagnostic marker. MiR–17–5p and miR–193a–5p in EVs may be involved in lung inflammation by influencing the forkhead box O (FoxO) signaling pathway and protein processing in endoplasmic reticulum. This study is one of the few studies which focused on the potential diagnostic role of miRNAs in BALF-EVs for pneumonia and the possibility to use them as new biomarkers for a rapid and early diagnosis.

Extracellular vesicles derived from Trichinella Spiralis larvae promote the polarization of macrophages to M2b type and inhibit the activation of fibroblasts

Trichinella spiralis (T. spiralis) is a globally distributed food-borne parasite that can coexist with the host for a long time after infection. Trichinella-derived secretions can regulate the immune response and fibroblasts of the host, but the specific mechanisms involved are still unclear. The purpose of this study was to investigate the role of T. spiralis larvae-derived extracellular vesicles (EVs) and their key miRNAs in the process of T. spiralis–host interaction. In this study, we found that the EVs of T. spiralis larvae, as well as miR-1-3p and let-7-5p, expressed in T. spiralis larvae-derived EVs, can promote the polarization of bone marrow macrophages to M2b type while inhibiting the activation of fibroblasts. These findings will contribute to further understanding of the molecular mechanisms underlying T. spiralis–host interactions.

Emerging roles for extracellular vesicles in Schistosoma infection

The co-evolution of Schistosoma and its host necessitates the use of extracellular vesicles (EVs) generated by different lifecycle stages to manipulate the host immune system to achieve a delicate balance between the survival of the parasite and the limited pathology of the host. EVs are phospholipid bilayer membrane-enclosed vesicles capable of transferring a complex mixture of proteins, lipids, and genetic materials to the host. They are nano-scale-sized vesicles involved in cellular communication. In this review, the author summarized the proteins involved in the biogenesis of schistosome-derived EVs and their cargo load. miRNAs are one cargo molecule that can underpin EVs functions and significantly affect parasite/host interactions and immune modulation. They skew macrophage polarization towards the M1 phenotype and downregulate Th2 immunity. Schistosoma can evade the host immune system's harmful effects by utilizing this strategy. In order to compromise the protective effect of Th2, EVs upregulate T regulatory cells and activate eosinophils, which contribute to granuloma formation. Schistosomal EVs also affect fibrosis by acting on non-immune cells such as hepatic stellate cells. These vesicles drew attention to translational applications in diagnosis, immunotherapy, and potential vaccines. A deep understanding of the interaction of schistosome-derived EVs with host cells will significantly increase our knowledge about the dynamics between the host and the worm that may aid in controlling this debilitating disease.

Roles of microRNAs and Long Non-Coding RNAs Encoded by Parasitic Helminths in Human Carcinogenesis

Infectious agents such as viruses, bacteria, and parasites can lead to cancer development. Infection with the helminthic parasite Schistosoma haematobium can cause cancer of the urinary bladder in humans, and infection with the parasites Clonorchis sinensis and Opisthorchis viverrini can promote cholangiocarcinoma. These three pathogens have been categorized as “group 1: carcinogenic to humans” by the International Agency for Research on Cancer (IARC). Additionally, the parasite Schistosoma japonicum has been associated with liver and colorectal cancer and classified as “group 2B: possibly carcinogenic to humans”. These parasites express regulatory non-coding RNAs as microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), which modulate genic expression in different biological processes. In this review, we discuss the potential roles of miRNAS and lncRNAs encoded by helminthic parasites that are classified by the IARC as carcinogenic and possibly carcinogenic to humans. The miRNAs of these parasites may be involved in carcinogenesis by modulating the biological functions of the pathogen and the host and by altering microenvironments prone to tumor growth. miRNAs were identified in different host fluids. Additionally, some miRNAs showed direct antitumoral effects. Together, these miRNAs show potential for use in future therapeutic and diagnostic applications. LncRNAs have been less studied in these parasites, and their biological effects in the parasite–host interaction are largely unknown.

Multifunctional Roles of MicroRNAs in Schistosomiasis

Schistosomiasis is a parasitic disease that is caused by helminths of the genus Schistosoma. The dioecious schistosomes mate and lay eggs after undergoing a complex life cycle. Schistosome eggs are mostly responsible for the transmission of schistosomiasis and chronic fibrotic disease induced by egg antigens is the main cause of the high mortality rate. Currently, chemotherapy with praziquantel (PZQ) is the only effective treatment against schistosomiasis, although the potential of drug resistance remains a concern. Hence, there is an urgent demand for new and effective strategies to combat schistosomiasis, which is the second most prevalent parasitic disease after malaria. MicroRNAs (miRNAs) are small non-coding RNAs that play pivotal regulatory roles in many organisms, including the development and sexual maturation of schistosomes. Thus, miRNAs are potential targets for treatment of schistosomiasis. Moreover, miRNAs can serve as multifunctional “nano-tools” for cross-species delivery in order to regulate host-parasite interactions. In this review, the multifunctional roles of miRNAs in the growth and development of schistosomes are discussed. The various regulatory functions of host-derived and worm-derived miRNAs on the progression of schistosomiasis are also thoroughly addressed, especially the promotional and inhibitory effects on schistosome-induced liver fibrosis. Additionally, the potential of miRNAs as biomarkers for the diagnosis and treatment of schistosomiasis is considered.

Host Liver-Derived Extracellular Vesicles Deliver miR-142a-3p Induces Neutrophil Extracellular Traps via Targeting WASL to Block the Development of Schistosoma japonicum

Schistosomiasis is an important neglected tropical disease. Interactions between the host immune system and schistosomes are complex. Neutrophils contribute to clearance of large pathogens primarily by releasing neutrophil extracellular traps (NETs). However, the functional role of NETs in clearing schistosomes remains unclear. Herein, we report that extracellular vesicles (EVs) derived from the liver of Schistosoma japonicum-infected mice (IL-EVs) induce NET release by delivering miR-142a-3p to target WASL and block the development of S. japonicum. WASL knockout accelerated the formation of NETs that blocked further development of S. japonicum. miR-142a-3p and NETs upregulated the expression of CCL2, which recruits macrophages that block S. japonicum development. However, S. japonicum inhibited NET formation in wild-type mice by upregulating host interleukin-10 (IL-10) expression. In contrast, in WASL knockout mice, IL-10 expression was downregulated, and S. japonicum-mediated inhibition of NET formation was significantly reduced. IL-EV-mediated induction of NET formation is thus an anti-schistosome response that can be counteracted by S. japonicum. These findings suggest that IL-EV-mediated induction of NET formation plays a key role in schistosome infection and that WASL is a potential therapeutic target in schistosomiasis and other infectious diseases.

From Inflammation to Fibrosis: Novel Insights into the Roles of High Mobility Group Protein Box 1 in Schistosome-Induced Liver Damage

Schistosomiasis is a chronic helminthic disease of both humans and animals and the second most prevalent parasitic disease after malaria. Through a complex migration process, schistosome eggs trapped in the liver can lead to the formation of granulomas and subsequent schistosome-induced liver damage, which results in high mortality and morbidity. Although praziquantel can eliminate mature worms and prevent egg deposition, effective drugs to reverse schistosome-induced liver damage are scarce. High mobility group box 1 (HMGB1) is a multifunctional cytokine contributing to liver injury, inflammation, and immune responses in schistosomiasis by binding to cell-surface Toll-like receptors and receptors for advanced glycation end products. HMGB1 is increased in the serum of patients with schistosomiasis and enables hepatic stellate cells to adopt a proliferative myofibroblast-like phenotype, which is crucial to schistosome-induced granuloma formation. Inhibition of HMGB1 was found to generate protective responses against fibrotic diseases in animal models. Clinically, HMGB1 presents a potential target for treatment of the chronic sequelae of schistosomiasis. Here, the pivotal role of HMGB1 in granuloma formation and schistosome-induced liver damage, as well the potential of HMGB1 as a therapeutic target, are discussed.

Semaphorins as Potential Immune Therapeutic Targets for Cancer

Semaphorins are a large class of secreted or membrane-bound molecules. It has been reported that semaphorins play important roles in regulating several hallmarks of cancer, including angiogenesis, metastasis, and immune evasion. Semaphorins and their receptors are widely expressed on tumor cells and immune cells. However, the biological role of semaphorins in tumor immune microenvironment is intricate. The dysregulation of semaphorins influences the recruitment and infiltration of immune cells, leading to abnormal anti-tumor effect. Although the underlying mechanisms of semaphorins on regulating tumor-infiltrating immune cell activation and functions are not fully understood, semaphorins can notably be promising immunotherapy targets for cancer.

Recombinant protein Schistosoma japonicum-derived molecule attenuates dextran sulfate sodium-induced colitis by inhibiting miRNA-217-5p to alleviate apoptosis

BACKGROUND

Inflammatory bowel disease (IBD) affects millions of people worldwide and has emerged as a growing problem in industrialized nations. The lack of therapeutic targets has limited the treatment of IBD. Studies found that parasitic nematode infections can ameliorate clinical and experimental colitis. Our previous study found that rSj16, a 16-kDa secreted protein of Schistosoma japonicum produced by Escherichia coli, has protective effects on dextran sulfate sodium (DSS)-induced colitis in mice. Apoptosis is an important factor in the pathogenesis of colitis. However, it is not clear whether the effect of rSj16 on colitis is related to apoptosis.

AIM

To investigate whether the protective effects of rSj16 on colitis is related to apoptosis and its mechanism.

METHODS

In-vivo, colitis was induced by DSS. The severity of colitis was assessed. WB was used to detect the changes of apoptosis-related genes in colon tissues. Q-PCR was used to detect the changes of miRNA-217-5p and HNF1B. In-vitro, WB was used to detect the changes of apoptosis-related genes in intestinal epithelial cells. TUNNEL staining and flow cytometry were used to detect cell apoptosis.

RESULTS

rSj16 attenuates clinical activity in DSS-induced colitis mice. TUNNEL staining and WB results showed that apoptosis was increased in colon tissue after treatment with DSS, and the apoptosis of colon tissue was significantly reduced after treatment with rSj16. Compared with normal mice, the expression of miR-217-5p was increased in colon tissue of DSS-induced colitis mice. In addition, the miR-217-5p target gene hnf1b was decreased after administration of DSS. After treatment with rSj16, the expression of miR-217-5p was decreased and the expression of HNF1B was increased compared with the DSS-treated group. When Etoposide was used in combination with miR-217-5p mimic on MODE-K cells, the expression of cleaved-Caspase-3 and Bax was increased, and Bcl-2 was decreased compared with only Etoposide treatment, the expression of HNF1B was significantly reduced, suggesting that miR-217-5p acts as a pro-apoptotic in colon epithelial cells and down-regulates the target gene hnf1b. After rSj16 administration in MODE-K cells, miR-217-5p expression was significantly decreased, HNF1B expression was increased, and apoptosis was reduced.

CONCLUSION

The protective effects of rSj16 on colitis is related to apoptosis and miRNA-217-5p may be a further target for therapeutic intervention against IBD.

Parasitic Helminth-Derived microRNAs and Extracellular Vesicle Cargos as Biomarkers for Helminthic Infections

As an adaption to their complex lifecycles, helminth parasites garner a unique repertoire of genes at different developmental stages with subtle regulatory mechanisms. These parasitic worms release differential components such as microRNAs (miRNAs) and extracellular vesicles (EVs) as mediators which participate in the host-parasite interaction, immune regulation/evasion, and in governing processes associated with host infection. MiRNAs are small (~ 22-nucleotides) non-coding RNAs that regulate gene expression at the post-transcriptional level, and can exist in stable form in bodily fluids such as serum/plasma, urine, saliva and bile. In addition to reports focusing on the identification of miRNAs or in the probing of differentially expressed miRNA profiles in different development stages/sexes or in specific tissues, a number of studies have focused on the detection of helminth-derived miRNAs in the mammalian host circulatory system as diagnostic biomarkers. Extracellular vesicles (EVs), small membrane-surrounded structures secreted by a wide variety of cell types, contain rich cargos that are important in cell-cell communication. EVs have attracted wide attention due to their unique functional relevance in host-parasite interactions and for their potential value in translational applications such as biomarker discovery. In the current review, we discuss the status and potential of helminth parasite-derived circulating miRNAs and EV cargos as novel diagnostic tools.

Understanding the Pathophysiology of Exosomes in Schistosomiasis: A New Direction for Disease Control and Prevention

Schistosomiasis is a parasitic disease endemic to freshwater areas of Southeast Asia, Africa, and South America that is capable of causing serious damage to the internal organs. Recent studies have linked exosomes to the progression of schistosomiasis. These structures are important mediators for intercellular communication, assist cells to exchange proteins, lipids, and genetic material and have been shown to play critical roles during host–parasite interactions. This review aims to discuss the pathophysiology of exosomes in schistosomiasis and their roles in regulating the host immune response. Understanding how exosomes are involved in the pathogenesis of schistosomiasis may provide new perspectives in diagnosing and treating this neglected disease.

Insights Into Exosomal Non-Coding RNAs Sorting Mechanism and Clinical Application

Exosomes are natural nanoscale bilayer phospholipid vesicles that can be secreted by almost all types of cells and are detected in almost all types of body fluids. Exosomes are effective mediators of cell–cell signaling communication because of their ability to carry and transfer a variety of bioactive molecules, including non-coding RNAs. Non-coding RNAs have also been found to exert strong effects on a variety of biological processes, including tumorigenesis. Many researchers have established that exosomes encapsulate bioactive non-coding RNAs that alter the biological phenotype of specific target cells in an autocrine or a paracrine manner. However, the mechanism by which the producer cells package non-coding RNAs into exosomes is not well understood. This review focuses on the current research on exosomal non-coding RNAs, including the biogenesis of exosomes, the possible mechanism of sorting non-coding RNAs, their biological functions, and their potential for clinical application in the future.

The challenging world of extracellular RNAs of helminth parasites

In the last years, cell free or extracellular RNAs (ex-RNAs) have emerged as novel intercellular messengers between animal cells, including pathogens. In infectious diseases, ex-RNAs represent novel players in the host-pathogen and pathogen-pathogen interplays and have been described in parasitic helminths from the three major taxonomic groups: nematodes, trematodes and cestodes. Altogether, it is estimated that approximately 30 percent of the world's population is infected with helminths, which cause debilitating diseases and syndromes. Ex-RNAs are protected from degradation by encapsulation in extracellular vesicles (EV), or association to proteins or lipoproteins, and have been detected in the excretion/secretion products of helminth parasites, with EV as the preferred extracellular compartment under study. EV is the generic term used to describe a heterogenous group of subcellular membrane-bound particles, with varying sizes, biogenesis, density and composition. However, recent data suggests that this is not the only means used by helminth parasites to secrete RNAs since ex-RNAs can also be found in EV-depleted samples. Furthermore, the use of pathogen ex-RNAs as biomarkers promise the advent of new diagnostic tools though this field is still in early stages of exploration. In this review, we summarize current knowledge of vesicular and non-vesicular ex-RNAs secretion in helminth parasites, their potential as biomarkers and the evidence of their role in parasite and host reciprocal communication, together with unanswered questions in the field.

Extracellular Vesicles: Schistosomal Long-Range Precise Weapon to Manipulate the Immune Response

Schistosomiasis (Bilharziasis), a neglected tropical disease that affects more than 240 million people around the world, is caused by infection with the helminth parasite Schistosoma. As part of their secretome, schistosomes release extracellular vesicles (EVs) that modulate the host immune response. The EV-harbored miRNAs upregulate the innate immune response of the M1 pathway and downregulate the differentiation toward the adaptive Th2 immunity. A schistosomal egg-derived miRNA increases the percentage of regulatory T cells. This schistosomal-inducible immunoediting process generates ultimately a parasitic friendly environment that is applied carefully as restrained Th2 response is crucial for the host survival and successful excretion of the eggs. Evidence indicates a selective targeting of schistosomal EVs, however, the underlying mechanisms are unclear yet. The effects of the schistosomes on the host immune system is in accordance with the hygiene hypothesis, attributing the dramatic increase in recent decades in allergy and other diseases associated with imbalanced immune response, to the reduced exposure to infectious agents that co-evolved with humans during evolution. Deciphering the bioactive cargo, function, and selective targeting of the parasite-secreted EVs may facilitate the development of novel tools for diagnostics and delivered therapy to schistosomiasis, as well as to immune-associated disorders.